Electrical controlling apparatus.



E. L. GALE, SR. ELECTRICAL CONTROLLING APPARATUS.

APPLICATION FILED MAY 2, 1912.

1,089,921 Patented Mar. 10, 1914 2 SHEETS-SHEET 1.

E. L. GALE, SR. ELECTRICAL CONTROLLING APPARATUS.

APPLICATION FILED MAY 2, 1912.

1,089,921. Patnted Mar.10,1911

2 SHEETSSHBET 2.

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ERNEST I. GALE, SR., OF YONKERS, YORK, ASS-IGNOR TO .OTIS ELEVATORCOMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTRICAL CONTROLLING APPARATUS.

- Specification of Letters Patent.

Patented Mar. 10, 1914.

Application filed Kay 2, 1912. Serial No. 694,816.

To aLZ whom it m (111 concern:

Be it known that I, ERNEST L. GALE, Sr., a citizen of the United States,residing at Yonkers, in the county of VVestchester and State of NewYork, have invented a new and useful Improvement in ElectricalControlling Apparatus, of which the following is a specification.

' My invention relates to alternating current electrical apparatus andmore particularly to means for insuring the demagnetization of analternating current brake magnet and operation of the brake, as thecurrent supply is cut off.

The invention herein is used in connection with an electric elevatoralthough it may have a more general application.

A serious objection to the use of alternating current brakes forelevators and other apparatus is due to residual magnetism which, whenthe current supply is cutofl, is

sometimes suflicient to prevent the operation of the brakes. This hasfrequently resulted in serious accidents.

An object of the present invention is to overcome this objection byproviding means that will insure the demagnetization of the brakemagnet.- The amount of residual magnetism in an alternating currentmagnet depends largely on the particular phase of the current at theinstant the circuit is opened. The magnetism rapidly fluctuates betweenmaximum value and zero owing to the current alternations. If the circuitis opened when the magnetic flux is at or near zero, there will ofcourse be little or no resid ual magnetism; but if the circuit is openedwhile the magnetic flux is large, the residual magnetism will beconsiderable.

In accordance with my invention, I provide means for momentarilyintroducing a high resistance in the brake magnet circuits, just beforethe circuits are opened. This permits a very small alternatin current toflow momentarily, which is sufficient to overcome any residualmagnetism, and thus insure the release of the magnet cores or armaturesand the application of the brake.

The present invention may be considered a modification of the inventionset forth in my co-pending application for patent on a brake magnetdemagnetizing device, Serial N 0. 571,899, filed July 14, 1910.

In the accompanying drawings, Figure 1 is a diagrammatic view of anelevator system embodying my invention; Fig. 2 is a diagrammatic viewshowing the arrangement of the brake coils; Fig. 3 shows a modificat1onof the arrangement disclosed in Fig. 1, the brake coils allbeingiconnected in series with the resistance; Figs. 4 and 5 showfurther modifications of the arrangement disclosed in Fig. 1.

The elevator system disclosed in Fig. 1 is not new except as it involvesa resistance and controlling circuits therefor in connection with thebrake mechanism. A brief description of the general arrangement willtherefore sufiice: A multi-phase system is shown in which current issupplied through the main wires 1, 2 and 3, which lead through a mainline switch 4 to the potential switch P, reversing switches R, R andmotor M. 011 the motor shaft is a traction sheave or hoisting drum 1) onwhich run the cables 5 connected to the car C and counterweight W.

-An alternating current brake B, which may be of usual construction, isprovided and comprises brake magnet coils a, a, b, as shown in Fig. 2. Astarting resistance Y is connected in the rotor circuit of the motor,said resistance being controlled by a series of accelerating magnets 0,d, e, 7. A controller K preferably located in the car controls thecircuits for the reversing switch magnets and the accelerating magnets,and thereby controls the normal operation of the car. If the lever 6 ofthe car controller K is moved for example to the right, a circuit forthe magnet coil of the reversing switch R is established which may betraced as follows: From the main wire 3 through conductor 7, coil 8 ofthe reversing switch R, conductor 9, contacts 10, 11, 12 of the carswitch, conductors 13 and 14 to the main wire 2. The magnet 8 beinenergized the reversing switch R is operate to a closed position andthereby establishes a circuit for the magnet coil of the potentialswitch P. This circuit may be traced from the main wire 3, throughconductor 15 and contacts 16 of the reversing switch R, conductor 17magnet coil 18 of the potential switch, conductor 19, slack cable switch20, speed governor switch 21, upper car limit switch 22, emergencyswitch 23 in the car, conductor 24, lower limit switch 25, and conductor14, to the main wire 2. The magnet 18 being thus energized, closes thepotential switch P and thereby completes the circuits for the stator ofthe motor. These circuits are as follows: The conductor 1 is connectedthrough contacts 26, conductor 27, contacts 28, and conductor 29 withone terminal of the motor. The main wire 8 is likewise connected throughpotential switch con tacts 30, conductor 31, contacts 32 of thereversing switch R, and conductor 33 to another terminal of the motor.The main wire 2 is connected directly to the motor independently of thepotential and reversing switches. The motor M therefore receives astarting current. The brake magnets are also energized as will be morefully set forth hereinafter, and the brake lifted to permit the motor tostart. The motor starts and runs at slow speed with a startingresistance Y in the rotor circuit. The operation of the car switch lever6 as above noted permits th cam block 35 to move downward, suehmovementbeing preferably retarded by a dashpot or other suitable means. This camblock permits the switches 36, 37, 38 and 39 to close in succession andthereby successively energize the magnets c, d, e and f. The circuitthrough the switch 36 for example may be traced as follows: From themain wire 2, through conductor 14, switch 36, conductor 40, coil ofmagnet c, conductor 29, reversing switch contacts 28, conductor 27,potential switch contacts 26, to the main wire 1. The magnet 0 beingenergized closes its switch and short-circuits the first sections of theresistance Y, thereby permitting an increase in the speed of the motor;The magnets d, e and f, are likewise operated in turn to shortcircuitthe remainder of the starting resistance in a series of steps, and thusgradually bring the motor up to full speed. When the reversing switchand potential switch were closed as above noted, circuits for the brakemagnet coils were established as follows: From the conductor 1, throughpotential switch contacts 26, conductor 41, brake magnet coils a, a,conductor 42, contacts 43 and 44 on the reversing switch R, and fromthence to the main wire 2. The brake coils b, b, likewise receivecurrent through a circuit including the main wire 3, potential switchcontacts 30, conductor 45, magnet coils b, b, conductor 46, reversingswitch contacts 43 and 44, and main wire 2. Between the conductors 42and 46 is connected aresistance X, comprising sections a: and m. At thejunction of said sections is connected a conductor 47 which leadsdirectly to the main wire 2 independently of the reversing switches. Thepurpose of the resistance X and conductor 47 is to permit a smallmomentary current through the brake magnet to insure its demagnetizationwhen the reversin switches are opened as will presently be escribed.

To stop the motor and car, the controller switch 6 is brought back tocentral position, thereby opening the switches 36, 37 38 and 39, tocause the startin resistance Y to be reinserted, and also to reak thereversing switch magnet circuit at the contacts 10, 12. The reversingswitch magnet being deenergized, the switch R opens, and cuts 05 thecurrent supply to the motor. The opening of the switch R also breaks thecircuit through the magnet 18 of the potential switch so that the latteris also opened. It.

should be here noted that a slight period of time elapses between theopening of the reversing switch and the potential switch, which time,however, I have found sulficient to accomplish the purpose of thepresent invention. When the reversing switch opens, the circuits for themagnet coils as above traced through the reversing switch contacts 43,44, are opened, but a small demagnetizing current is still allowed toflow temporarily through the resistance X. That is the circuit throughthe magnet coils a, a is completed by way of conductor 42, resistance wand conductor 47. The circuit for the coils b and I) is likewisecompleted through conductor 46, resistance on and conductor 47. Theresistances m, w are high,

so that only a very small alternating current is permitted through themagnet coils. This current, however, is sufficient to overcome anyresidual magnetism in the brake magnets, completely demagnetizing thelatter and insuring the brake being lifted. Without this resistance, thebrake magnet circuits might be opened at an instant when there was alarge magnetic flux through the magnet, which would permit a high residual magnetism which might be suflicient to prevent the brake beinglifted. With the present invention, the small fluctuating current withthe resistance in the circuits overcomes any such residual magnetism.The opening of the potential switch opens the brake circuits, but theslight time elapsing between the opening of the reversing switch andpotential switch is sulficient to permit the resistance X to accomplishits purpose.

Fig 3 shows a modified arrangement in which the conductor 47 of Fig. 1leadingfrom the resistance X is omitted. With this arrangement it willbe seen that between the opening of the reversing switch and thepotential switch the brake magnet coils are connected in series throughthe resistance X. The circuit may be traced as follows: From the main 1,through contacts 26, conductor 41, brake coils a, a, the resistance X,brake coils b, b, conductor 45 and contacts 30, main wire 3. Theprinciple of operation is the same as already described in connectionwith Fig. 1.

Fig. 4 shows a further modification in which the brake circuit contacts43 and 44 of the reversing switches are omitted. The

brake magnet in this instance comprises two single phase coils a", b.When the potential and reversing switches are closed, the brake coilsreceive current by way of the 5 reversing switch contacts 28, 32. Whenthe reversing switch R is opened in stopping the motor, resistances Xare momentarily introduced into the brake magnet circuits, until thepotential switch P opens.

Fig. 5 illustrates another modification in which each of the brake coilsa", and b" is normally connected across two of the mains while the motoris receiving current. One terminal of the coil a is connected throughconductor 41, and the potential switch to the main wire 1. One terminalof the coil 6" is likewise connected through conductor 45 to the mainwire 3. The opposite terminals of said coils are connected together andthrough the common wire 50,

contacts 51 of the reversing switch, and wire 52 to the main wire 2. Itwill thus be seen that each of the brake coils is directly across two ofthe main wires and receives a single phase current. When the reversingswitch R is opened, the circuit through the common wire 50 is broken atthe contacts 51. This leaves the brake coils momentarily inseries acrossthe mains 1 and 3, until the potential 80 switch opens to cut. off allcurrent supply to the brake coils. The coils being thus temporarilyconnected in series, the current therethrough and consequently themagnetic flux is materially reduced, with a conse- 86 quent diminutionof the residual magnetism when the circuit is opened.

The operation when the car switch has been moved to the left issubstantially the same as above described in connection with the leverbeing moved to theright, except that the reversing switch R will beoperated and the phase relation changed to cause the motor to operate ina reverse direction. It will be-understood of course that although Ihave shown my invention applied to a multiphase system it is equallyapplicable to a system employing a single phase current.

I wish not to be limited to the particular construction and arrangementshown, .as

various modifications might be made within the scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is 6 1. In electrical controlling apparatus, the combination of abrake, a brake magnet,

. means to connect and disconnect said magnet to and from a source ofalternating current supply, and means operable independcut of theoperation of the brake automatically to momentarily increase theresistance of the magnet circuit before it is disconnected from the saidsource of current suply. p 2. In electrical controlling apparatus, the

combination of a motor, an electromagnetic brake, circuit controllingdevices operable in succession to connect and disconnect the motor toand from a source of current supply, a brake magnet circuit controlledby said devices, and means automatically to reduce the current throughthe brake magnet during the interval between the successive operation ofsaid devices.

3. In electrical controlling apparatus, the combination of an electricalcircuit, switches in series in said circuit, means to effect thesuccessive operation of said switches, an electromagnet, a circuittherefor controlled by said switches, and means automatically 8 toreduce the current through said magnet during the interval between theoperation of said switches.

4:. The combination of an electric motor, switches operable insuccession to establish a circuit for the motor, means to eliect theopening of said switches in succession to open the motor circuit, anelectromagnetic brake having its circuit-controlled by said switches,and means automatically to reduce the current in the brake magnet duringthe interval between the opening of said switches.

5. The combination of an electric motor, reversing switches therefor, anadditional 5 switch in circuit with the reversing switches, means toeffect the successive operation of said switches, an electromagneticbrake having its circuit controlled by said switches, and meansautomatically to modify the brake circuit and thereby reduce the currentin the brakemagnet in the interval of time between the operation of saidswitches.

6. The combination of an alternating current electric motor, reversingswitches therefor, an additional switch in circuit with the reversingswitches, an electro-magnetic brake having a. circuit connected througha reversing switch and said additional switch to a source of currentsupply, a resistance, and circuit connections from the brake magnetthrough a reversing switch and said resistance to the source of currentsupply independent of said additional switch.

7. The combination of an alternating current motor, reversing switchestherefor, a potential switch between the reversing switches and thecurrent supply mains, an electro-magnetic brake, switch contacts in 120the brake magnet circuit, and connected to be operated by a reversingswitch to complete the brake magnet circuit therethrough and through thepotential switch, resistances, andcircuit connections to complete abrake 125 magnet circuit through said resistance and the potentialswitch independently of the reversing switches when the brake is inreleased position.

8. The combination of an alternating cur- 130 rent electric motor,reversing switches there for, an electromagnetic main line switch in.

are operated to open the motor circuits and the brake is in releasedposition.

10. The combination of an alternating current motor, reversing switchestherefor, an electromagnetic brake, a resistance, and means associatedwith the reversing switches for automatically introducing saidresistance momentarily in the brake circuit when a reversing switch isoperated to open the motor circuit and the brake is in releasedposition.

11. The combination of an electric motor, a switch controlling the motorcircuit, an electromagnetic brake, and means associated with said switchand controlled thereby automatically to modify the brake circuit andreduce the current therethrough momentarily when said switch is operatedto open the motor circuit and the brake is in released position.

12'. The combination of an alternating current electric motor, reversingswitches therefor, an electromagnetic switch between the reversingswitches and a source of current supply, an electromagnetic brake, cir

cuit connections leading from the said electromagnetic switch to thebrake magnet, brake circuit contacts carried by the reversingswitches,'return wires leading from the brake magnet through saidcontacts to the source of current supply, a resistance connected betweensaid return wires and the circuit connections from said resistance tothe source of current supply independent of the reversing switches.

13. The combination of an alternating current motor, a main line switchadapted to connect the motor to a source of current supply, anelectromagnetic brake, a circuit therefor through said switch,resistance in the brake magnet circuit, a reversing switch, and meansoperable thereby to shortcircuit said resistance and to include saidresistance in the brake magnet circuit when the brake is in releasedposition.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses.

ERNEST L. GALE, SR.

Witnesses:

EDWARD H. STEELE, GEORGE D. Rosn.

